Pyra-Metho-Carnil Suppresses CD73-associated Macrophage Infiltration in KRAS-mutant Colorectal Cancer

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Pyra-Metho-Carnil (PMC) previously showed suppression of macrophage differentiation with mutant (mt) Kirsten rat sarcoma (KRAS) tumors.
• Integrative proteomics identified 5'-nucleotidase ecto (NT5E)/CD73 as a KRAS-regulated protein linking KRAS signaling to tumor immune microenvironment (TIME) remodeling.

Purpose of the Study:

• To investigate if PMC modulates CD73-associated pathways during macrophage differentiation.
• To explore the therapeutic potential of PMC in mt-KRAS colorectal cancer (CRC).

Main Methods:

• THP-1 cells were differentiated and treated with PMC or a CD73 inhibitor (CD73i).
• Three-dimensional (3D) co-culture assays used wild-type (wt) KRAS or mt KRAS spheroids.
• Macrophage infiltration was assessed via live-cell imaging and immunohistochemistry (IHC).
• Co-localization of CD73+ tumor cells and CD68+ macrophages was examined in clinical CRC specimens.

Main Results:

• PMC reduced macrophage infiltration into mt-KRAS spheroids, an effect also seen with CD73i.
• PMC demonstrated broader antitumor effects by suppressing both CD73-mediated infiltration and tumor cell proliferation.
• Clinical mt-KRAS CRC tissues showed significant clustering of CD73+ tumor cells and CD68+ macrophages at invasive fronts.

Conclusions:

• PMC suppresses macrophage infiltration and reprograms TIME via CD73 regulation.
• PMC exhibits superior therapeutic value over CD73i in mt-KRAS CRC by targeting tumor growth and immune evasion.
• Clinical CD73 expression correlates with macrophage clustering in CRC, supporting PMC's therapeutic relevance.